TB rates rise among HIV+ Latinos in Southern Cal

Study sounds alarm about trend

The overall public health picture looks good with tuberculosis (TB) rates continuing to decline in both HIV-infected and general United States populations. But these facts mask a disturbing trend that researchers found in Southern California.

Hispanics from Mexico increasingly are co-infected with HIV and TB, a new study finds.1

"The reason we started this work is because in San Diego, we've found that HIV/TB co-infection is pretty consistent and did not seem to be going down even though there was an overall decline in TB rates," says Timothy C. Rodwell, MD, PhD, MPH, an assistant professor in the division of global public health in the school of medicine at the University of California - San Diego in La Jolla, CA.

"We wanted to see what was going on," Rodwell says. "Was there something on the surface or something deeper underneath?"

Examining HIV/TB co-infection rates over time in different demographic groups, the researchers found that a disease that affected all groups in the 1990s now is almost exclusively Hispanic, he says.

"HIV/TB co-infection has been improving in the other two groups, but it's failing to improve in Hispanics," Rodwell says.

The study found that of 5,172 TB cases from 1993 through 2007 in San Diego County, CA, 8.8% were also infected with HIV.

Over this same period, the proportion of cases among Hispanics increased significantly. Cases of HIV/TB co-infection among non-Hispanic Whites and Blacks decreased.

Test HIV patients for TB

"The majority of cases that are Hispanic are people born in Mexico, and there's a lot of bi-national movement between Mexico and the United States — some 60 million border crossings a year in this area," he adds. "So it means the relationship is complicated."

HIV clinicians should test all patients with HIV for tuberculosis, and infectious diseases clinicians should test all TB patients for HIV, he says.

The study identified the scale and scope of the HIV/TB co-infection phenomenon, as well as identifying risk factors of people with co-infection.

"We found that young, male injection drug users (IDUs) were much more likely to have HIV/TB co-infection," Rodwell says. "This is a hard group to find and a hard group to treat, as well."

The study specifically found that co-infection rates were higher among this cohort of men in the 30 to 49 years age range.1

Both diseases require time and resources for proper treatment, and the fact that many of the male IDUs with co-infection also are Hispanic makes it even more challenging.

"This is one of the toughest groups to find and treat, and we don't know what proportion of this group is undocumented," Rodwell says. "All we know is whether they're born in Mexico or the United States, and the majority of HIV/TB cases are born in Mexico."

These patients typically are diagnosed late in their disease.

"They show up severely ill with both HIV and TB, so we never had a chance to work preventatively with this population," Rodwell says. "If we can identify them early, we can get them into treatment and treat the latent disease before it becomes active."

About 70% of all TB cases in San Diego are among foreign-born residents, and 80% of TB/HIV cases are among Hispanics, he says.

"San Diego's TB incidence is double that of the rest of the United States, so even though we're improving, we're not improving at the same speed as the rest of the nation," he adds.

There is a possibility that San Diego's HIV/TB co-infection rate is the result of people contracting tuberculosis in Mexico, where TB is more common, and then moving to the United States where they then contract HIV, Rodwell explains.

"People might be contracting HIV here quite quickly because of social disruption," he says.

Although the new study looks at HIV/TB co-infection in Southern California, its implications should inform all practice decisions made by all American clinicians.

"Everybody with HIV absolutely should be tested for TB," Rodwell says. "If a patient is in a risk group — young, male, IDU — then there's no question this person should be tested for HIV and quite regularly."

Reference

  1. Rodwell TC, Barnes RFW, Moore M, et al. HIV-Tuberculosis co-infection in Southern California: evaluating disparities in disease burden. Am J Pub Health 2010: E-published ahead of print.